Introduction: Making accurate predictions about a stroke patient’s language/speech-motor outcome and recovery potential is a challenge. We previously showed that a combined variable of lesion site and size pertinent to relevant white matter language structures, the Arcuate Fasciculus lesion load (AF-LL), correlated highly with measures of speech fluency in chronic aphasic patients (Marchina et al., 2011; Wang et al., 2013). However, studies in motor recovery and other domains have shown that behavioral measures in the acute stroke phase might be equal or better predictors of recovery compared to lesion measures. Whether or not any of these measures follow a proportional recovery rule, has not been established.
Hypothesis: To evaluate whether acute aphasia measures (overall WAB score) and/or acute lesion measures (e.g., AF-Lesion Load) predict recovery from aphasia.
Methods: Over a period of several years, patients presenting with acute aphasia were evaluated using a bedside version of the Western Aphasia Battery complemented by picture naming tests, automatic speech measures, and custom-made word/phrase spoken and sung test. A total of 100 acute patients were assessed of which 56 followed up at 3 months. Lesion maps drawn on diffusion-weighted images were used to calculate lesion loads of a probabilistic Arcuate Fasciculus (AF) tract derived from matched elderly healthy control subjects. Analyses included correlations between recovery potential and actual recovery and other predictors of 3 months outcome. AF-LL was regressed with the overall WAB score, measures of speech fluency and naming ability (using the Boston Naming Test).
Results: The overall bedside WAB score in the acute stroke period was the best predictor of the overall WAB score at 3 months (R2=0.60). This predictor was slightly improved when a measure of speaking-singing dissociation was added to the model. Lesion-load of the AF was also a good predictor of WAB score at 3 months (R2=0.48), but did not improve outcome predictions of the WAB score by itself. Overall acute aphasic patients followed a proportional recovery rule, but only recovered about 56% of what was theoretically possible.
Conclusion: Language and Speech-Motor Outcome after stroke can be predicted best by a bedside WAB score.